Oil IT Journal interview - David Johnson, Petrolink

Oil IT Journal hears from Petrolink CTO on Witsml certification and learns more about the standard, the new Energistics transfer protocol and on managing Witsml data.

What’s behind Witsml certification.

Our implementation of the release passed the Energistics automated software testing and certification program. This new approach replaces previous certification programs and brings consistency and objectivity to the testing process. We have a particular interest in this as I am a co-chair of the Witsml SIG.

What does this entail?

Witsml is an open industry community. We try to keep the herd moving in the right direction and figure out where we should go tomorrow. We recently released the new Energistics transfer protocol for public review. ETP has been a focus for several years as the community looks beyond simple SOAP and separates data and transport mechanics, making it easier to add new stuff.

Why was this not done before?

Hindsight is a great thing! ETP fixes this issue, adding just what we need. We are now focusing on data management and have added new objects to make it possible to share quality assessments and add context. This will also enable data audit and traceability. With the rise of deviated drilling, managing trajectory data is increasingly important.

What does Witsml bring to Petrolink?

Actually we use and need lots of standards but we find Witsml to be one of the most active and open communities solving oil and gas problems.

What others are there?

A lot! Wits is still widely used as are LIS, LAS, DLIS and even CSV files. DLIS and WITS do have communities but they are not very active. We also see a lot of standards coming in from process control. OPC is a big contender here. But Witsml was designed by and for oil and gas.

But OPC is at a lower level?

Yes and it has a different footprint. But you may want to integrate some data from the process world. For instance to monitor a BOP stack. This is easiest to implement at the OPC level and you can share summary data from service providers via Modbus/Profibus. We take results from OPC and ‘upscale’ to Witsml. There may be other ways of doing this, but I am biased! Petrolink also does data aggregation. Company X has some data, company Y has more data and we combine them, adding context.

Witsml is the industry-favored format?

Yes. Our first thought is to use the data structures somehow, even if it was not designed for data management.

What is the situation now with validation of Witsml data? Oil IT Journal validates its newsfeed with the W3C’s validator. Why isn’t this facility offered by Witsml?

It is now although it is true that the Witsml community resisted certification for years. But this did not stop users (like us) from using a parser to check conformity. With V1.4.1.1, we realized that an extra step was needed, one that would not be a barrier to use. Today, the free Energistics reference server gives an unbiased opinion on data structure and behavior, although this approach is not as rigorous as your RSS Feed validation.

Which is certified? Server or client?

For now it’s the server. But as we move to ETP and away from XML and with an order of magnitude more data, we will need a more structured process like a validator.

ETP is not XML?

No it is a binary encoding of data in say XML or Profibus. You can also use ETP as internal transfer mechanism for proprietary data. ETP leverages the HDF open packaging standard that was championed by the Resqml community. It also uses the Apache Avro framework.

Speaking of Resqml, is the Semantic Web getting take-up in the larger Energistics community?

The community is often asked by oils for more context and extra information types like the relationship between real time and static, reported data. A report is a snapshot of data at a point in time. This requires thinking about things at a corporate level – for instance tying Witsml to SAP. In this context, combining semantic metadata with Witsml objects could be a means of taking stuff along the data chain. The Energistics data management group is looking at this. In fact I am working on a paper for PNEC on Data Management Challenges and WITSML.

Who pays for all this?

We are 100% staffed by volunteers. There are 75 in Schlumberger and 4-5 companies working on the project. More from Petrolink.

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